Alfalfa is a cool season
perennial legume living from three to twelve years, depending on variety
and climate. It resembles clover with clusters of small purple flowers.

The
plant grows to a height of up to 1 metre (3 ft), and has a deep root
system sometimes stretching to 4.5 metres (15 ft). This makes it very
resilient, especially to droughts. It has a tetraploid genome. The plant
exhibits autotoxicity, which means that it is difficult for alfalfa
seed to grow in existing stands of alfalfa. Therefore, it is recommended
that alfalfa fields be rotated with other species (for example, corn or
wheat) before reseeding.